clang-tools-extra/clang-tidy/bugprone/NonZeroEnumToBoolConversionCheck.cpp

   1 //===--- NonZeroEnumToBoolConversionCheck.cpp - clang-tidy ----------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "NonZeroEnumToBoolConversionCheck.h"
  10 #include "../utils/Matchers.h"
  11 #include "../utils/OptionsUtils.h"
  12 #include "clang/AST/ASTContext.h"
  13 #include "clang/ASTMatchers/ASTMatchFinder.h"
  14 #include <algorithm>
  15
  16 using namespace clang::ast_matchers;
  17
  18 namespace clang::tidy::bugprone {
  19
  20 namespace {
  21
  22 AST_MATCHER(EnumDecl, isCompleteAndHasNoZeroValue) {
  23   const EnumDecl *Definition = Node.getDefinition();
  24   return Definition && Node.isComplete() &&
  25          std::none_of(Definition->enumerator_begin(),
  26                       Definition->enumerator_end(),
  27                       [](const EnumConstantDecl *Value) {
  28                         return Value->getInitVal().isZero();
  29                       });
  30 }
  31
  32 } // namespace
  33
  34 NonZeroEnumToBoolConversionCheck::NonZeroEnumToBoolConversionCheck(
  35     StringRef Name, ClangTidyContext *Context)
  36     : ClangTidyCheck(Name, Context),
  37       EnumIgnoreList(
  38           utils::options::parseStringList(Options.get("EnumIgnoreList", ""))) {}
  39
  40 void NonZeroEnumToBoolConversionCheck::storeOptions(
  41     ClangTidyOptions::OptionMap &Opts) {
  42   Options.store(Opts, "EnumIgnoreList",
  43                 utils::options::serializeStringList(EnumIgnoreList));
  44 }
  45
  46 bool NonZeroEnumToBoolConversionCheck::isLanguageVersionSupported(
  47     const LangOptions &LangOpts) const {
  48   return LangOpts.CPlusPlus;
  49 }
  50
  51 void NonZeroEnumToBoolConversionCheck::registerMatchers(MatchFinder *Finder) {
  52   // Excluding bitwise operators (binary and overload) to avoid false-positives
  53   // in code like this 'if (e & SUCCESS) {'.
  54   auto ExcludedOperators = binaryOperation(hasAnyOperatorName(
  55       "|", "&", "^", "<<", ">>", "~", "|=", "&=", "^=", "<<=", ">>="));
  56
  57   Finder->addMatcher(
  58       castExpr(hasCastKind(CK_IntegralToBoolean),
  59                unless(isExpansionInSystemHeader()), hasType(booleanType()),
  60                hasSourceExpression(
  61                    expr(hasType(qualType(hasCanonicalType(hasDeclaration(
  62                             enumDecl(isCompleteAndHasNoZeroValue(),
  63                                      unless(matchers::matchesAnyListedName(
  64                                          EnumIgnoreList)))
  65                                 .bind("enum"))))),
  66                         unless(declRefExpr(to(enumConstantDecl()))),
  67                         unless(ignoringImplicit(ExcludedOperators)))),
  68                unless(hasAncestor(staticAssertDecl())))
  69           .bind("cast"),
  70       this);
  71 }
  72
  73 void NonZeroEnumToBoolConversionCheck::check(
  74     const MatchFinder::MatchResult &Result) {
  75   const auto *Cast = Result.Nodes.getNodeAs<CastExpr>("cast");
  76   const auto *Enum = Result.Nodes.getNodeAs<EnumDecl>("enum");
  77
  78   diag(Cast->getExprLoc(), "conversion of %0 into 'bool' will always return "
  79                            "'true', enum doesn't have a zero-value enumerator")
  80       << Enum;
  81   diag(Enum->getLocation(), "enum is defined here", DiagnosticIDs::Note);
  82 }
  83
  84 } // namespace clang::tidy::bugprone